Cut potatoes into thick slices Chop / slice onion
Heat oil in a LARGE frying pan, add the potatoes & onion and stew gently, partially covered, for 30 minutes, stirring occasionally until the potatoes have softened.
Strain potatoes and onions through a colander into a large bowl (set strained oil aside).
Beat the eggs separately, then stir into the potatoes.
Heat a little of the strained oil into a smaller (omlette) pan - tip everything into the pan and cook on a moderate heat, using a spatula to shape the omlette into a “cushion”.
When almost set, invert on a plate and slide back into the pan and cook for a few more minutes. Invert twice more, cooking the omlette briefly each time and pressing the edges to keep the cushion shape.
Slide on to a plate [and cool for 10 minutes before serving.]
from BBC Good Good